Middleware Testing Patterns

<default_to_action> When testing enterprise middleware, ESBs, or message-driven systems:

1. VALIDATE message routing logic (content-based, header-based, recipient list)
2. TEST message transformations end-to-end (input format -> output format)
3. VERIFY dead letter queue handling (poison messages, retry exhaustion)
4. ASSERT message ordering and sequencing with correlation IDs
5. EXERCISE error handling and compensation patterns
6. TEST protocol mediation (SOAP-to-REST, sync-to-async)
7. VALIDATE EIP patterns (splitter, aggregator, content enricher, normalizer)

Quick Pattern Selection:

• Message routing issues -> Content-based router tests
• Transformation failures -> Schema-in/schema-out validation
• Lost messages -> DLQ and retry pattern tests
• Protocol bridging -> Mediation round-trip tests
• Complex flows -> Correlation ID tracing tests